For the purposes of this question, please note that I am not asking for general advice on buying tools, but rather, I'm trying to identify the cases in which it may be practical and useful to have two or more of the same tool. One reason is to help new woodworkers avoid paralysis by analysis--it doesn't make sense to spend a significant amount of time agonizing over the purchase of some tools since you'll most likely want to keep at least two of the same tool in service at the same time anyway, for convenience or some other purpose.

The conventional wisdom when it comes to buying tools is that you should buy your last tool first, because you'll save a lot of money over endlessly upgrading. For example, many people start out with a cheap jobsite table saw and upgrade several times, finally ending up with a cabinet saw, when they could have just bought the cabinet saw from the start and saved a lot of money and frustration over time.

On the flip-side, it's far too easy to overanalyze a tool purchase. When I started building my tool collection, I spent an enormous amount of time agonizing over which tools to buy. For example, I could have just bought a set of chisels for $10, or a nicer set for $60, or really nice chisels for $60+ apiece. I agonized over it for weeks before buying two nice chisels, but it wasn't until after I was given a cheaper set of chisels that I started actually using my chisels. In hindsight, I should have just bought the cheap chisels and upgraded as needed, because in the case of chisels it's good to have a nicer set for finer work and a cheaper set for "banging around"--scraping glue, working reclaimed wood with embedded dirt and grit, etc.

In what cases is it useful to have more than one of the same tool (even, perhaps, the same exact tool), and why? And, on a related note, when is it advantageous to buy a cheap tool first and later buy a second (or third, or fourth...), possibly better, tool of the same type without rendering the first tool worthless?

I have 3 main tool chests: one on the second floor (bedrooms), one on the main floor, and one in the basement. That way I don't have to carry tool chests up and down the stairs.
– Treow WyrhtaJul 18 '16 at 18:42

5 Answers
5

One thing to keep in mind is that in many cases, a really low-end tool will just be frustrating. If you only need to save up for a couple months to buy better tools and your window of opportunity for woodworking will still be open at that time go ahead and wait. You may even find some great deals in the meantime.

But if you have a choice between saving up for a year (or longer) and buying a cheaper tool now, you may be better off buying the cheaper tool now and getting some experience with it before buying a better one later. Often you can still put the old one to good use.

Power Tools & Accessories

Drill

If money is tight, it's okay to pick up a corded drill for $20 or so. But now that you can get cordless lithium-ion drill/impact driver combo kits for $100 or less on sale, it makes sense to start out with a good cordless drill rather than a $50 NiCad drill. Everyone should have at least 2 drills to avoid having to constantly switch back and forth between drill bits and driving bits.

One for drilling

One for driving

Additional drill(s) may be used for countersinking, other sizes of bits, or other specialty bits

Drill bits

Drill bits dull and break. Even if you sharpen your own bits, some are more difficult to sharpen and others are cheap enough that you can basically consider them consumable.

multiples of the driver bits that you use frequently, especially those that strip and wear easily (e.g., #2 Phillips)

Router

Practically nobody has just one router, so it hardly matters which router you buy starting out. Although it's tempting to go with the beefiest router you can afford, you don't need a particularly powerful router for handheld routing. In fact, a more powerful router might tempt you into taking deeper cuts than you should. A decent trim router is actually a very practical first router purchase, and although I've been shunning trim routers ever since they started to grow in popularity a few years ago, Marc Adams convinced me I should have bought one a long time ago.

Trim router: incredibly versatile, and eventually you'll want one so if you're on a limited budget, you can buy a decent trim router. A nice side benefit is that the 1/4" bits that you'll need to use with a trim router are cheaper than 1/2" bits. Many accessories are also available, such as an offset adapter base, plunge base, angled bases, collet adapters for your Dremel (rotary multi-tool) bits, etc.

Plunge router: good for many tasks; not as good as a fixed-base router in a router table

Fixed-base router: great for mounting in a router table

Additional routers: many people have anywhere from 5 to 15+ routers. Some might be dedicated to specific tasks for a given project to avoid constantly needing to swap and/or readjust bits, while others may each be permanently dedicated to a specific bit (e.g., a dedicated router for use with a dovetail jig).

Router bits

It's useful to have some of the same profile router bits in both 1/4" and 1/2" shanks depending on which router you will use for a given task.

One circular saw dedicated to cutting reclaimed wood that may contain nails

A second circular saw with a good blade on it, for clean cuts

Planer (and/or Jointer?)

Some people will swap a dull set of knives into their planer and/or jointer for cleaning up reclaimed wood. The problem is, swapping knives can be a pain or you might not have an extra set of knives on hand suitable for this purpose (maybe you just had all your knives sharpened).

A second planer or jointer can be useful to clean up reclaimed wood before processing it on your good tools. Personally, I'd suggest a second planer but not necessarily a second jointer, since a typical woodworker is more likely to have a wide planer than a wide jointer, and you can use a belt sander or table saw to edge joint reclaimed lumber after planing the faces.

If you work exclusively with clean lumber, then a second planer or jointer doesn't provide much benefit unless you regularly transport your machinery to a jobsite.

Random Orbital Sander

Smaller (e.g., 5") sander with a small stroke length for fine finish sanding

Larger (e.g., 6") sander for faster sanding of large panels

Additional sanders can also have other benefits

Two sanders let you sand more quickly (one in each hand)

Multiple sanders with different grits can save some time, though changing paper is pretty quick

Miter saw

Whether your first one is a fixed 90 degree chop saw, compound miter saw, or sliding compound miter saw, you can probably still find a use for it if and when you upgrade later on down the road:

One semi-permanently set up as a chop saw for 90 degree crosscuts on long boards or, for example, for trimming cabinet or door stiles after final assembly

One set to whatever weird angle you need to repeatedly cut today

Oscillating spindle sander

It can be handy to have more than one oscillating spindle sander (or one OSS and one spindle sander attachment for your drill press) with different grits and/or spindle sizes, or one for sanding and one for buffing (a paint roller works for buffing). Depending on the type of work you do, you may or may not get much use out of a second spindle sander.

Oscillating multi-tool

Although it's easier to swap blades on newer oscillating multi-tools, if you have to keep switching back and forth between blades, or if you have an older oscillating multi-tool on which blade changes aren't as easy, it makes sense to buy a second oscillating multi-tool.

Lathe

big one in the (possibly unheated) shop

small portable one for inside the house or smaller secondary shop, or for travel

Lathe accessories

multiple chucks and/or faceplates so you can work on multiple pieces without having to unmount them and hope when you remount the incomplete piece, you get it mounted exactly the same as before (more an issue with faceplates, but some guys in my turners group use the same argument for owning multiple $300+ chucks, too)

multiple chisels/gouges of the same type so you don't have to stop and resharpen as often

Hand Tools

Clamps, of course

Everyone knows you can never have enough clamps, though certain types are more useful than others in mass quantities. You'll want to buy most clamps in pairs.

Cheap pipe clamps and F-style bar clamps are useful, and you can put off buying more expensive parallel clamps by using cauls.

Gear clamps and cheap "Quick Grip"-style clamps are handy for holding stop blocks and for temporarily holding things in place for alignment. You probably won't need more than a few of these.

More expensive, heavy-duty Quick Grip and parallel clamps are useful for glue-ups

C clamps aren't that useful in the woodshop these days, but if you do metalworking or welding in your projects it might be handy to have a couple on hand.

Band clamps, corner clamps, and other specialized clamps can be useful depending on the types of projects you build.

Hand saw

Various types of handsaws in different configurations are useful depending on the type of work you do, especially joinery. These aren't exactly duplicates, but it's useful to have the following:

Classic hand saw (multiple lengths are convenient but not necessary)

Traditional bow saw

Hacksaw

Coping saw

Rip dovetail saw

Crosscut carcass saw

Rip tenon saw

Hand planes

There are a lot of opinions about which 1 or 3 hand planes you should buy first, but I'll just focus on which types of hand planes you may want to own in multiples.

4, #4-1/2, or #5 planes in at least a couple configurations depending on what you do.

"Normal" setup

Smoother

Scrub plane (e.g., if you dimension your lumber by hand)

I don't have a very large collection but haven't found other planes as useful in duplicate, other than perhaps getting multiple sizes of router planes or shoulder planes, for example. However, some people keep duplicates so they don't have to resharpen as often.

Chisels

You'll definitely want more than one set of chisels, so it isn't important to buy a good set up front. No matter what chisels you buy, you'll have to learn to sharpen them anyway, and it isn't that difficult to learn.

Cheap set of bench chisels to "bang around." Depending on your budget, these could range from $5 to $70 for a set of 4 or 5. This set isn't necessarily for opening paint cans, but for scraping glue squeeze-out after it has dried, for working reclaimed or dirty lumber, and more generally to learn how to sharpen and use chisels. If your first chisels are expensive, you may be too afraid of ruining them. Oh, and you'll undoubtedly drop one of your chisels on a concrete floor somehow, so do that to a cheap one before you do it to a nice one.

Nicer set(s) for fine work. Eventually you'll want some nicer bench chisels which hold their edges better, and maybe after using a cheaper set you'll decide whether or not it's important to you to have the nicer chisels be socket chisels so you can swap handles for different tasks. You may also buy more specialized chisels, such as mortising chisels or skew chisels if you decide you like hand-cutting your joinery.

Different sizes and weights of mallets and hammers are good for different tasks.

Marking gauges

It's really convenient to have at least a couple marking gauges so you can leave them set to critical dimensions when laying out cuts, especially for joinery.

At least two more pin or (preferably) knife marking gauges

At least one standard-size one for general use

Preferably a small one for easier handling when laying out dovetails

Round wheel marking gauge for marking around curves

Mortise gauge for (surprise!) marking mortises

Pencils

Have enough pencils lying around so one is always within reach.

Mechanical pencils are good but buy a lot of lead

Also have a knife or sharpener handy at all times.

Marking knives

Marking knives are good for laying out very precise lines where a pencil line would be too thick. In combination with a square, they're great for extending lines around corners and for making precise registration marks for starting cuts. You can also use them to sharpen your pencils.

various types of knives are good depending on the work you're doing, but even a hobby knife like an Exacto knife can work pretty well as a marking knife

a knife with one side flat (not beveled) registers better against a straightedge

(Adhesive) tape

Tape has at least a million uses in the shop, from protecting against tearout to holding pieces together, to standing in for clamps (or even making improvised clamps). Because it's a consumable, you'll always go through more than one roll.

painter's tape (aka "blue tape")

double-sided, fiber-reinforced carpet tape

duct tape--maybe not as good as some other tapes in a lot of applications, but it usually works fine in a pinch

whatever other types of tape you find useful

Tape measures

Even with at least a half dozen tape measures floating around, I'm lucky if I can ever find more than one, and sometimes even finding that one takes me a couple minutes if I forgot to put it away the last time I used it!

Anyone that says the only have a couple of clamps is a liar. Pencils... lots of pencils. Also this is a great question to send new users to.
– MattMay 29 '15 at 16:00

Add tape, cases of tape. Painter's tape is what I use most, however, your mileage may vary.
– Adam ZuckermanMay 29 '15 at 16:29

1

tl;dr - you can never have too many tools :)
– StevenMay 29 '15 at 16:50

5

Another note on buying a cheaper tool first - you may just find out what features are really important to you prior to spending big bucks on a nicer tool.
– DoresoomMay 29 '15 at 17:03

1

@Doresoom that's a great point; you definitely learn quickly which things you don't like about a cheaper tool. Sometimes you may not even realize what features you sacrificed by buying the cheaper tool. When I bought my first cordless drill, I was blown away by the one-handed keyless chuck. Now I wouldn't buy a new drill without one, but if I hadn't bought the good tool first, I never would have known to look for that feature. But it has also gone the other way for me, when I bought a nicer tool but would have been just as happy without one or more of the extra features.
– rob♦May 29 '15 at 17:12

Grow with the tools and the job. When your subject matter expertise exceeds the abilities of the tools -> upgrade them. Do not expect that great tools will automatically give great results or a great craftsman. Your skills will guide you.

However, first you would need to know which tool is suitable for which job because the best tool used wrong would damage it and not create the desired result.

Welcome to the site! Can you think of any tools and corresponding reasons (preferably not already mentioned) in which you would keep the old tool and continue using it even after upgrading?
– rob♦May 29 '15 at 20:37

We've already talked about using the old circular saw for cutting wood with nails, but I have another one: my first hammer drill got superseded by by absolutely lovely SDS rotary hammer (it chips/chisels! how could I not love it?), so the poor first drill gets to mix mortar. Or maybe it gets loaned to the neighbor who needs to drill some concrete...
– Aloysius DefenestrateMay 30 '15 at 3:56

My friend Dennis works on boats, woodworking, he got frustrated when he was on the boat and he did not have a tool and had to then go back to his workshop and get it, and the reverse is also true when the tool is on the boat and he is working in the workshop and does not have it. For myself, I work on electronics, but I have several work benches, three in the garage and two more in the house. There's never enough screwdrivers so I buy enough screwdrivers and pliers and wrenches so I do not spend a lot of time walking back and forth looking for that one tool I know I have, but I can't find it between the five benches, the tool kit in my car and the vehicle standing on the forecourt... Better have more than one or I'd go crazy for one

Sharpening stones with different grits - because while you can do any sharpening job with a fine stone, you can save considerable time using a coarser stone when starting a job that requires significant material removal.

Safety glasses - I'm a safety nut, so I can't work without glasses. Spares ensure that I won't misplace this essential item and delay work.

Clean-up brushes - I keep a couple lying around within reach to sweep away dust and shavings.

Shop-vacs - my shop is somewhat large (24' x 32'), and shop vacs are a nuisance to drag around.

Spare blades - a dinged blade on a planer or jointer can be a show-stopper. Doesn't suck to have spares.

Hex (Allen) wrenches - keep the right size(s) next to each tool that requires it(them) for set-up/adjustment.

+1 for the hex wrench comment. I use masking tape to attach the correct size wrenches to the back of the tool to save the time spent going through every single wrong sized wrench before finally getting the right sized one.
– FreeManMay 5 '16 at 19:40

You need multiple instances of a tool .... when you need multiple instances of the tool. This question answers itself as you actually work on projects. Buy what you need when it significantly eases a task you do frequently, or when you can't see any other way to complete the task, or when you really don't like the one(s) you have on hand and believe you have found one that will resolve those difficulties.

There are a very few tools which are frequently used in pairs, such as wrenches (holding one side while turning the other side). There are a few which are used so often that it may be worth having several copies stored in multiple places so they are always available where and when you need them. But waiting and letting actual need/use drive this is the single best way to avoid wasting money on unneeded tools... Which leaves you more money to spend on getting the tools you do need, or buying higher-quality versions thereof.